Ten Israeli teenagers were killed Thursday in a flash flood in Nahal Tzafit — which is typically extremely dry — located in the southern part of the country. The victims belonged to a group of around 25 young students, who were members of a pre-army preparatory program.

The group was hiking close to the Tzafit stream, near the Dead Sea, when the flood struck. Late Thursday, police arrested the principal of the Bnei Tzion pre-military academy and an instructor on suspicion of negligent homicide. The Tel-Aviv-based institution had arranged the hike that resulted in the death of the 10 students, while 15 others were rescued, of which two suffered from hypothermia.

One of the teenage girls who was killed in the flash flood told friends a day earlier she was worried for her safety during the hike, the Israel Television News Company reported. In messages sent to her friends on Whatsapp, the girl wrote: "I can't believe I'm actually going hiking in weather like this. It doesn't make sense to go to a place that's completely flooded. It's tempting fate. We're going to die – I'm serious."

To this, a member of the WhatsApp group, who was not going on the trip, answered: "It's very strange that they took you out like this, excuse me."

Another replied: "Haha, don't exaggerate. I'm sure they are sensible and will definitely take you to other places. And sleep in a closed space."

Police have so far identified nine victims as: Ella Or, from the settlement of Ma’ale Adumim; Gali Belali, from the central city of Givatayim; Agam Levi, from Moshav Herut in central Israel; Shani Samir, from the central town of Shoham; Adi Ra’anan, from the coastal community of Mikhmoret; Yael Sadan and Maayan Barhum from Jerusalem; Romi Cohen, from Moshav Maor in the north and Tzur Alfi, from the central town of Mazekeret Batya.

The tenth victim, who was missing, was declared dead after her body was found late Thursday.

In a statement on Twitter, Israeli Prime Minister Benjamin Netanyahu called the incident a “terrible disaster” and praised the first responders.

"Israel grieves the promising young lives that were cut off by this tragedy in the Arava," Netanyahu said. "We embrace the families with grief and pray for the speedy recovery of the wounded."

Police have launched an investigation into the incident. So far, the two people arrested in the case have been questioned. A third suspect was also questioned and later released to house arrest, local media reported, citing police.

Agencies that collect rainfall and flooding information in the vicinity had issued warning on Wednesday and Thursday of risk of flooding after heavy rainfall in the area. The Israel Meteorological Service also issued a warning on the risk of flooding in the Dead Sea region, as even relatively small quantities of rainfall in the desert could lead to flash floods.

One of the teenagers, who survived the flash flooding, recalled seeing “bodies in the water” as 10 feet high waves killed his friends.

“I saw bodies floating in the water, I didn’t know if they were alive or if what I saw were dead bodies,” the boy told Hadashot News through his father.

“At one point there was a wave that was 3 or 4 meters high,” the boy told his father. “I was holding on to one of my friends really tight… but we couldn’t cope with the massive flow of water... She slipped away from me in front of my eyes."

Israeli President Reuven Rivlin said the entire country was “mourning the loss of young promising lives in the heavy disaster.”